Conductor for electrical fire-alarm systems



(No Model.)

W. A. BARNES. v GONDUOTOR P03 ELECTRICAL FIRE ALARM SYSTEMS. No. 378,078, Patented Feb. 21, 1888.

I [NVE r00 7 ATTORNEY .UNIT'ED STAi-Es PATENT "Ctr-Ion.

WILLIAM A. BARNES, OF BRIDGEPORT, CONNECTICUT.

CONDUCTOR FOR ELECTRICAL FIRE-ALARM SYSTEMS.

SPECIFICATION forming part of Letters Patent Nc. 378,078, dated February 21, 1888.

' Application filed September 26, 1887.

To all whom it may concern.-

Be it known that 1, WILLIAM A. BARNES, of Bridgeport, Fair-field county, Connecticut, have invented anew and useful Improvement in Conductors for Electrical Fire-Alarm Systems, of which the following is-a specification.

My inventionrelates to a conductor designed for use in connectionwith electrical fire-alarm systems; and it consists in awire composed of lengths or sections of a metal or alloy fusible at a low temperature, the said lengths or sections being united by joints formed of a metal or alloy fusible at a temperature still lower than that at which thewire sections will melt.

In the accompanying drawings, Figure 1 represents a portion of my new conductor. Fig. 2 is an electrical diagram showing an arrangement ofthe said conductor with the mech-' anisrn of a fire-alarm system.

Similar letters of reference indicate like parts.

The object of this invention is to provide a means of detecting the presence of an unduly high temperature under two different conditionsnamely, first, at certain points when the temperature of the adjacent atmosphere exceeds a certain degree, and, second, at all points along and in the vicinity of the conductor when the temperature exceeds a certain higher degree.

, The conductor to this end is made of sections of wire A, Fig. 1, integrally formed of fusible metal, fusible alloy, or any other known metal compound which is fusible at a comparatively low temperature. In practice it is better to select for this purpose any fusible alloy which will melt at about 500 Fahrenheitsuch,for example, as tin two parts and zinc four parts, or tin three parts, zinc four parts, or the series of alloys of bismuth, lead, and tin ranging in proportions from eight parts bismuth, sixteen parts lead, and eighteen parts tin to eight parts bismuth, thirty-two parts lead, and forty parts tin. The sections of wire made from such an alloy are united by joints B, which may be formed by soldering with a fusible alloy which will melt at a much lower temperaturesuch, for example, as five parts bismuth, three parts lead, and two parts tin, which melts at 199 Fahrenheit, or bismuth, lead, and tin alloys, such as the preceding, to whicha small percentage of mercury is added,

Serial No. 250,643. (No model.)

thus still further lowering the fusing-point. A great many so-called fusible alloys melting at widely-varyingtemperatures are well known in the arts, from which selections can readily be made to suit the special circumstances under which this conductor may be employed,so that further detailed reference to particular compositions is unnecessary. of this construction is as follows: The sections A may be made of any desired length, and the wire be led wherever protection from fire is needed, and especially through concealed localities, as between the beams of buildings, under floors, through plastering, &c., the parallel or adjacent parts (a a a, Fig. 2) of the Wire being in such proximity-say three or four feet aparta-s that an incipient fire cannot far progress before meeting a wire and melting it.

The advantage- The joints B of the wire, as has been stated, I

said conductor therefore serves the double purpose of guarding against undue rise in atmospheric heat and against actual conflagration.

Actual flame will rupture the conductor at any point, but a temperature, say, equal to that of boiling water, for example, may cause its rupture only at a joint. The body of the conductorseotions A may therefore be made of alloys of greater tensile strength than would be possible were the whole conductor to be integrally formed of the material used in forming the joints.

Fig. 2, which shows in diagram a simple arrangement of fire-alarm system, illustrates the above-described mode of using the conductor. At C is shown a series of beams, along the tops of which the conductor may be laid. The sections A of the conductor may come in direct contact with the beams, and the joints Bmay come in the spaces between the beams, as shown. Now the parts A on top of the beams might be completely covered by flooring or otherwise inclosed in material poorly conducting heat, so that an undue elevation in adjacent atmospheric temperature might not be transmitted through the shielding material prompt- ]y. The joints B, however, are exposed, and therefore any undue increase of heat of the air between the beams at once causes rupture of the conductor at these joints.

The mechanism in the illustrative fire-alarm system shown in Fig. 2 is as follows: E is a battery or other source of electricity, to one pole of which is connected theconductor A, the other pole being grounded. The current from the battery passes through the conductor to the coil of an electro-magnet, F, which thus becomes energized, and thence to ground. The magnet F therefore normally attracts an armature, G, which is in shunt-circuit J with any form of electrical alarm H, battery, and ground. WVhen the conductor is ruptured at any point, the magnet F releases its armature, which, meeting a contact-point, I, establishes circuit through the shunt J, and so causes the alarm to operate.

It is of course to be understood that in the above mechanism the line-circuit onlyis to be made of the compound fusible wire above described, and not the coil of magnet F.

In another application for Letters Patent filed simultaneously herewith by me, Serial No. 250,642, I have described and claimed a conductor for electrical fire-alarms consisting of a wire integrally formed of a fusible metallic compound; and in still another application for Letters Patent, also filed simultaneously herewith by me, Serial No. 250,644, I have specifically described and claimeda conductor for electrical fire-alarms consisting of sections of wire of copper, iron, or other metal 3 5 having a comparatively high fusing point united by joints of fusible metal. These inventions I do not herein claim. The particular alarm system herein set forth is merely illustrative. I do not claim the same nor limit 0 my invention to use therewith.

I claim- 1. As a new article of manufacture, a conductor for electrical fire-alarn1s,consisting of a Wire formed of sections of metallic compound 45 fusible at a certain comparatively low temperature, united by joints formed of a metallic compound fusible at a temperature lower than that of the fusing-point of said sections, substantially as described.

2. In combination with an electrical-alarm system, a conductor formed of sections of wire of a metallic compound fusible at a certain comparatively low temperature, united by joints formed of a metallic compound fusible 55 at a temperature lower than the fusingpoint of said sections, substantially as described.

WILLIAM A. BARNES.

Witnesses: 7

DAVID B. LOCKWOOD, ALFRED B. BEERS. 

